1. Field of the Invention
The present invention relates to a group III nitride semiconductor laser diode.
2. Related Background Art
Patent Literature 1 discloses a Fabry-Perot semiconductor laser diode having a lasing wavelength band of 500 nm or longer. The semiconductor laser diode has n-type semiconductor layers, a light emitting layer, and p-type semiconductor layers. These layers are stacked on a primary surface of a GaN substrate. The primary surface includes a non-polar m-plane. The n-type semiconductor layers include an n-type GaN cladding layer and an n-type InGaN optical guiding layer. The p-type semiconductor layers include a p-type GaN cladding layer and a p-type InGaN optical guiding layer.
Patent Literature 2 discloses a laser device having a lasing wavelength band of 425 nm to 450 nm. The laser device has an n-type GaN cladding layer, an active layer, and a p-type cladding layer. These layers are stacked on a primary surface of a GaN substrate. The primary surface includes a c-plane. In addition, the laser device has GaN optical guiding layers. A GaN optical guiding layer is provided between the n-type cladding layer and the active layer. The other GaN optical guiding layer is provided between the p-type cladding layer and the active layer. An indium-containing nitride semiconductor layer is provided between the GaN optical guiding layer and the active layer.